Abstract
Among 75734 newborns submitted to TSH screening, 22 had documented hypothyroidism and 6 were found at the time of recall (3d-4th week) to have persistently high plasma TSH levels (40 to 300 μU/ml), normal plasma T4 (9.1 to 12.3 μg/dl) and T3 (1.5 to 2.6 ng/ml), normal thyroid scintiscan and urine iodine. 4 of them treated with T4 increased their plasma T4 in the hyperthyroid range without decreasing TSH, and their TSH did not rise when this treatment was stopped. In all 6, plasma TSH decreased spontaneously to normal at 3-8 months. TSH was normal in fathers but persistently elevated in mothers (52 to 460 μU/ml) contrasting with normal T4, T3, scintiscan, thyroid iodine uptake and response to exogenous TSH. No thyroid autoantibodies were found. In vitro studies demonstrated in plasma of infants and mothers lack of antiTSH antibodies, abnormal TSH dilution curves, and correction of the apparently high TSH levels by addition of normal rabbit serum (3 and 25 nl/incubate). These data suggest the placental transmission of a maternal plasma substance blocking antiTSH rabbit γ globulin, and must lead to avoid inadequate diagnosis and therapy in neonates.
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Gendrel, D., Feinstein, M., Ingrand, J. et al. High radioimmunoassayable plasma TSH in newborns with normal thyroid function and in their mothers. Pediatr Res 15, 74 (1981). https://doi.org/10.1203/00006450-198101000-00018
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DOI: https://doi.org/10.1203/00006450-198101000-00018